You'll need 12 wooden toothpicks coated with nonstick spray. In a small bowl, mix apple, cheese, bread crumbs, chopped thyme, lemon juice and half the salt mixture. On a cutting board, lightly press each chicken breast flat with one hand; using a sharp knife, carefully cut into side of breast to form a deep, horizontal pocket (do not pierce top, bottom or far side of breast).

Divide the apple mixture into 4 portions and stuff into chicken pockets. With the prepared toothpicks, pin closed. Sprinkle the remaining salt mixture over breasts. Dredge chicken in flour to lightly coat; tap off excess flour. (At this point, chicken can be refrigerated, covered, up to 6 hours.)

Heat oil in a large nonstick skillet over medium-high heat. Add chicken and brown 3 minutes per side. Pour 1/2 cup of the apple cider and the broth into skillet; add thyme sprigs. Bring mixture to a boil; reduce heat to low, cover and simmer 5 to 7 minutes or until chicken is cooked through and stuffing registers 165°F on an instant-read thermometer.

Remove chicken to a serving plate; cover with foil to keep warm. Whisk mustard and remaining 1/4 cup cider into juices in skillet; boil mixture 3 minutes on high until reduced and slightly thickened. Spoon sauce over chicken and serve.

A Part of Hearst Digital Media
Country Living participates in various affiliate marketing programs, which means we may get paid commissions on editorially chosen products purchased through our links to retailer sites.